Whew, day 3 was epic! I’m glad I got through all that! Day 4 (I hope) will be a bit easier. Now that I’ve got things “basically” working, it should be mostly a matter of getting a few more API calls doing what they need to do.

Step 1 – Basic handling of onPause:

First of all, right now when I restart the App without reinstalling it, I get a white screen. I think this is due to some multitasking feature on the Android where it shoves the App into the background and tells it to pause. When unpaused, I need to reload the graphics. Fixing this was pretty trivial, I just added a few lines to the onPause() method to save state and basically shutdown.

Step 2 – Removing the title bar:

When I start my game, there is a title that says “Galcon” in text on the top. I think that is part of the default app generation. I’ll want to remove that. First of all, in “res/layout/main.xml” I commented out the TextView. This had no effect, but at least I cleared out some junk. This page appears to explain how to hide the title bar (I found by adding .Fullscreen it hides the Status Bar as well.)

http://developer.android.com/guide/appendix/faq/commontasks.html – modify AndroidManifest.xml:

<application android:icon=”@drawable/icon” android:theme=”@android:style/Theme.NoTitleBar.Fullscreen”>

Step 3 – Adding onTouchEvent handling:

I really want to start playing the game – so I’m going to add some input event handling. I’ll do this from the top level in my Activity by adding a onTouchEvent handler. The documentation for MotionEvent was a bit opaque, but I worked it out and here’s how to handle events and deal with MultiTouch. It seems like something is severely broken about the API, but this was the only way I could get MultiTouch to work in Galcon. It appears to only work with 2 fingers.

    public boolean onTouchEvent(final MotionEvent e) {
        for (int i = 0; i<e.getPointerCount(); i++) {
            boolean masked = false;
            switch(e.getActionMasked()) {
                case MotionEvent.ACTION_POINTER_DOWN:
                case MotionEvent.ACTION_POINTER_UP:
                    masked = true;
                break;
            }
            if (masked && i != e.getActionIndex()) { continue; }
            float x = e.getX(i); float y = e.getY(i);
            float dx = 0; float dy = 0;
            if (e.getHistorySize()!=0) {
                dx = x - e.getHistoricalX(i,0);
                dy = y - e.getHistoricalY(i,0);
            }
            int pid = e.getPointerId(i);
            int type = 0;
            switch(e.getActionMasked()) {
                case MotionEvent.ACTION_DOWN: type=EVT_DOWN; break;
                case MotionEvent.ACTION_MOVE: type=EVT_MOTION; break;
                case MotionEvent.ACTION_OUTSIDE: type=EVT_MOTION; break;
                case MotionEvent.ACTION_POINTER_DOWN: type=EVT_DOWN; break;
                case MotionEvent.ACTION_POINTER_UP: type=EVT_UP; break;
                case MotionEvent.ACTION_UP: type=EVT_UP; break;
                case MotionEvent.ACTION_CANCEL: type=EVT_UP; break;
            }
            event(type,(int)x,(int)y,0,pid+1,(int)dx,(int)dy,0,0);
            if (masked) { break; }
        }
        return true;
    }

This works okay, except my Nexus One has a different screen resolution than my iPhone, so all my code is handling things a bit off. I added a native call in onSurfaceChanged to tell my game the size of the screen. In my event handler I translate for the game.

Step 4 – Keyboard handling:

To play the multi-player game, I need to have the pop-up keyboard work. On the Droid, of course, this isn’t needed, but for the Nexus One and possibly other future devices it is.

This is apparently easier said than done. More on it in day 5!

This entry was posted on Friday, July 23rd, 2010 at 9:39 pm and is filed under android, galcon. You can follow any responses to this entry through the RSS 2.0 feed. Both comments and pings are currently closed.